About a Bug Rated 5 out of 5 stars
dear ASANO, Thank you so much for your nice quick answer.
when i read your reply i decide to found which add-on installed has conflict with "Work Offline".
i installed new fressh Firefox on my another computer that did not have any Mozilla applications installed before on it.
then installed Work Offline as first add-on.
then other my lovely add-ons one by one. step by step check "Work Offline" feature discussed about it.
but i found nothing.
I think now it is a feature by Firefox by own itself.
Now i found that can move "Work Offline 2.0" icon on Add-On bar just to bottom left corner of Firefox and bottom right corner.
also after other last add-ons icons inside Add-On bar.
also i can move "Work Offline" icon to everywhere in Navigation Toolbar.
it is not so important to me that can't move to each place i want in Add-On bar.
be comfort. take it easy.
all users like me just want its main feature from "Work Offline"
that they want an icon to make Firefox go to Offline or Online mode without using Firefox File menu.
I Love it.
thank you again for your time to write and develop this nice Add-On on lovely Firefox.
take it easy and continue.